Digital television (DTV) is an emerging market today. Deployment of terrestrial broadcasting began during 2005 and the market is currently moving toward handheld-oriented broadcast services that can withstand mobility of the receivers. DVB-H and T-DMB are going to be widely deployed for mobile TV, whereas DVB-T is already widely deployed for nomadic-to-portable reception conditions.
Time slicing is a technology uniquely employed by DVB-H. It allows the transmission to occur in time slots. The main objective of this feature is power saving at the receiver. However, all other standards (DVB-T, T-DMB, ISDB-T) do not have this mechanism and they rely on continuous reception conditions.
GPS is by now a well known technology that is widely exercised by handheld/PDA devices. GPS is essentially supported in two modes: assisted and non-assisted. In assisted mode, the receiver gets the sky maps from source network (e.g., a cellular operator) and these maps together with measurements of timing and Doppler calculations allow the receiver to determine precise location of the receiver. In non-assisted mode, the receiver has also to decode the sky maps from the satellite transmissions. The non-assisted mode requires mostly reception in bursts that length around 1 minute or so. The assisted mode requires reception of some hundreds of milliseconds, but only partially continuous. In any case, the GPS receiver will need few milliseconds at least every now and awhile to perform reception.
A problem arises when the two subsystems share the radio/antennae such that when one subsystem is operational the other one cannot perform reception.
Thus, a strong need exists for techniques to enable digital television and GPS coexistence.
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